Commonly, three-phase power is fed into a distribution network, carried from a substation to customers via feeders. Each customer is generally a one-phase entity and is powered by one of the three phases of the feeder. Depending on the distribution of customers on each phase and the variation of load over time, the total load on the three phases can be unbalanced in a distribution system. Unbalanced phases can lead to higher energy losses and a decrease in the lifetime of grid assets such as substation transformers. Unbalanced phases also affect equipment utilization and limit the maximum load that can be supplied to customers. Moreover, phase imbalances are expected to increase in the future with the introduction of heavier loads such as electric vehicles.
Existing phase balancing approaches require power measurements from customers and from possible balance point locations in the grid or distribution network. This requires a communication infrastructure to carry measurements from customer sensors to the utility, which is generally expensive to deploy and may not always be available or reliable. Additionally, existing phase balancing approaches require a demand response signal to be sent to the customers to change consumption and/or supply to balance the loads. This similarly requires a communication infrastructure between the utility and customers. Further, existing phase balancing approaches can include rewiring customers to different phases to balance the loads. This is an expensive manual operation and includes the risk that one fixed configuration of phase assignments may not work under all conditions.
Consequently, a need exists for distributed techniques that balance the load on the three phases dynamically and autonomously.